IJAAS International journal of ADVANCED AND APPLIED SCIENCES EISSN: 2313-3724, Print ISSN:2313-626X Frequency: 12 Volume 4, Issue 11 (November 2017), Pages: 1-10 ---------------------------------------------- Original Research Paper Title:  Prediction of the trajectory of an irregularly shaped body moving through a resistive medium with high velocities Author(s):  Elvedin Kljuno *, Alan Catovic Affiliation(s): Mechanical Engineering Faculty, University of Sarajevo, Sarajevo, Bosnia and Herzegovina https://doi.org/10.21833/ijaas.2017.011.001 Abstract: A model was made for prediction of the trajectory of an irregularly shaped body moving through a resistive medium with high velocities, using data for aerodynamic forces obtained from numerical simulations. For a different orientation of the body with respect to the velocity vector of the center of mass, the aerodynamic resistance force is different for two reasons: the exposed surface area is different and the shape is different. In this regard, 216 numerical simulations of airflow around of the body of an irregularly shaped body in different orientations were carried out, for one full rotation (around one axis of rotation) of the body, with angular increments of 15 (0 -360), for the following velocities: 0.6, 0.8, 1, 1.2, 1.3, 1.5, 2, 3 and 4 Mach. The outcome of these simulations is the resistance forces and aerodynamic moments as the result of motion of the body in various directions relatively to the body. After the simulations had been performed, the results of the resistance forces and aerodynamic moments were used to integrate the equations of motion with an assumption that the irregularly shaped body had a continuous rotation all the way along the trajectory with relatively high angular velocities. With this assumption, an effective aerodynamic force was calculated which takes into consideration that the aerodynamic force varies due to the rotation of the body. The results show that the trajectory of an irregularly shaped body is curved in space because the side component of the aerodynamic force cannot be ignored because of the irregular shape of the body, which leads to significant lateral movement of the body from the initial direction of flight.  © 2017 The Authors. Published by IASE. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Keywords: Dynamics, Modelling, Trajectory estimation, Aerodynamic force Article History: Received 29 June 2017, Received in revised form 4 September 2017, Accepted 5 September 2017 Digital Object Identifier:  https://doi.org/10.21833/ijaas.2017.011.001 Citation: Kljuno E and Catovic A (2017). Prediction of the trajectory of an irregularly shaped body moving through a resistive medium with high velocities. International Journal of Advanced and Applied Sciences, 4(11): 1-10 Permanent Link: http://www.science-gate.com/IJAAS/V4I11/Kljuno.html ---------------------------------------------- References (8) AASTP (2010). AASTP-1: Manual of Nato safety principles for the storage of military ammunition and explosives (one Edition). Allied Ammunition Storage and Transport Publication, NATO/PFP.  Anderson Jr JD (1991). Fundamentals of aerodynamics. MacGraw-Hill, New York, USA.      Fluent ANSYS (2011). ANSYS fluent theory guide. ANSYS Inc., 15317: 724-746.      Hoerner SF (1965). Fluid-dynamic drag: practical information on aerodynamic drag and hydrodynamic resistance. Hoerner Fluid Dynamics, New York, USA.      Kljuno E and Catovic A (2017a). Instability estimation of irregularly shaped bodies moving through a resistive medium with high velocity. International Journal of Advanced and Applied Sciences, 4(9): 70-79. https://doi.org/10.21833/ijaas.2017.09.009  Kljuno E and Catovic A (2017b). Determination of the center of pressure and dynamic stability for irregularly shaped bodies. International Journal of Advanced and Applied Sciences, 4(10): 1-9. https://doi.org/10.21833/ijaas.2017.010.001  Pope SB (2000). Turbulent flows. Cambridge University Press, Cambridge, UK. https://doi.org/10.1017/CBO9780511840531  Schamberger RL (1971). An investigation of the use of spin-stabilized cubes as fragment simulators in armor evaluation (No. GAM/MC/71-8). M.Sc. Thesis, Air Force Institute of Technology, Graduate School in Wright-Patterson Air Force Base, Ohio, USA.